Neptunusrex.........
That my old flower IMHO, is a load of bolleaux!! Hats should be worn all the time in doors. I think this confusion has arisen somewhere in the training system when someone must have hinted that you should take your hat off indoors and then everyone (and subsequent generations) seemed to decide that they didn't have to wear hats indoors. It has irked me for a long, long time that Service people took their hats off when entering a building whether it be SHQ or Tescos - I think it is wrong and unmilitary. For example if you entered an Officer's office, the first thing you should do is salute the officer, but you can only do that when wearing your hat. So as far as I know hats should be worn indoors - end of.